@jrc03c/js-math-tools/src/range.test.mjs

some math tools for JS

import { DataFrame, Series } from "./dataframe/index.mjs"
import { expect, test } from "@jrc03c/fake-jest"
import { forEach } from "./for-each.mjs"
import { isEqual } from "./is-equal.mjs"
import { range } from "./range.mjs"

test("tests that ranges of values can be generated correctly", () => {
  expect(range(-10, 10).a).toBe(-10)
  expect(range(-10, 10).b).toBe(10)
  expect(range(-10, 10).step).toBe(1)
  expect(range(-10, 10, 0.5).step).toBe(0.5)
  expect(range(0, 10).length).toBe(10)
  expect(range(-10, 10).length).toBe(20)
  expect(range(10, -10).length).toBe(20)
  expect(range(5, 10, 0.5).length).toBe(10)
  expect(range(0, 10).toArray()).toStrictEqual([0, 1, 2, 3, 4, 5, 6, 7, 8, 9])
  expect(range(2, 5, 0.5).toArray()).toStrictEqual([2, 2.5, 3, 3.5, 4, 4.5])
  expect(range(5, -5, 2).toArray()).toStrictEqual([5, 3, 1, -1, -3])
  expect(range(2n, 5n).toArray()).toStrictEqual([2n, 3n, 4n])
  expect(range(0n, 10n, 2n).toArray()).toStrictEqual([0n, 2n, 4n, 6n, 8n])
  expect(() => range(5, -5, -2)).not.toThrow()
  expect(() => range(0, 10, -5)).not.toThrow()

  !(() => {
    const x = range(-10, 10)
    const values = []
    const indices = []

    x.forEach((v, i) => {
      values.push(v)
      indices.push(i)
    })

    expect(isEqual(values, x.toArray())).toBe(true)
    expect(isEqual(indices, range(0, x.length).toArray())).toBe(true)
  })()

  const wrongs = [
    NaN,
    "foo",
    true,
    false,
    null,
    undefined,
    Symbol.for("Hello, world!"),
    [2, 3, 4],
    [
      [2, 3, 4],
      [5, 6, 7],
    ],
    x => x,
    function (x) {
      return x
    },
    { hello: "world" },
    new Series({ hello: [10, 20, 30, 40, 50] }),
    new DataFrame({ foo: [1, 2, 4, 8, 16], bar: [1, 3, 9, 27, 81] }),
  ]

  forEach(wrongs, a => {
    forEach(wrongs, b => {
      forEach(wrongs, c => {
        expect(() => range(a, b, c)).toThrow()
      })
    })
  })
})